I'm 14 years old and 5'3" and 90 pounds.i rarely sit dwn and I'm up and moving alotDo I need 2 wrry about cals?

You're underweight! people who are 5'3" are usually 100 pounds or a bit higher. What you need to worry about is to EAT more. But don't become obese or anything. Once you've gotten about 110 pounds you're at normal weight and perfectly fine. ;)